[mirror_edk2.git] / MdePkg / Library / BaseLib / SynchronizationMsc.c

/** @file\r
  Implementation of synchronization functions.\r
\r
  Copyright (c) 2006 - 2007, Intel Corporation<BR>\r
  All rights reserved. This program and the accompanying materials\r
  are licensed and made available under the terms and conditions of the BSD License\r
  which accompanies this distribution.  The full text of the license may be found at\r
  http://opensource.org/licenses/bsd-license.php\r
\r
  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,\r
  WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.\r
\r
  Module Name:  SynchronizationMsc.c\r
\r
**/\r
\r
#include "BaseLibInternals.h"\r
\r
//\r
// Microsoft Visual Studio 7.1 Function Prototypes for read write barrier Intrinsics\r
//\r
void    _ReadWriteBarrier (void);\r
#pragma intrinsic(_ReadWriteBarrier)\r
\r
\r
#define SPIN_LOCK_RELEASED          ((UINTN) 1)\r
#define SPIN_LOCK_ACQUIRED          ((UINTN) 2)\r
\r
/**\r
  Retrieves the architecture specific spin lock alignment requirements for\r
  optimal spin lock performance.\r
\r
  This function retrieves the spin lock alignment requirements for optimal\r
  performance on a given CPU architecture. The spin lock alignment must be a\r
  power of two and is returned by this function. If there are no alignment\r
  requirements, then 1 must be returned. The spin lock synchronization\r
  functions must function correctly if the spin lock size and alignment values\r
  returned by this function are not used at all. These values are hints to the\r
  consumers of the spin lock synchronization functions to obtain optimal spin\r
  lock performance.\r
\r
  @return The architecture specific spin lock alignment.\r
\r
**/\r
UINTN\r
EFIAPI\r
GetSpinLockProperties (\r
  VOID\r
  )\r
{\r
  // @bug May use a PCD entry to determine this alignment.\r
  return 32;\r
}\r
\r
/**\r
  Initializes a spin lock to the released state and returns the spin lock.\r
\r
  This function initializes the spin lock specified by SpinLock to the released\r
  state, and returns SpinLock. Optimal performance can be achieved by calling\r
  GetSpinLockProperties() to determine the size and alignment requirements for\r
  SpinLock.\r
\r
  If SpinLock is NULL, then ASSERT().\r
\r
  @param  SpinLock  A pointer to the spin lock to initialize to the released\r
                    state.\r
\r
  @return SpinLock\r
\r
**/\r
SPIN_LOCK *\r
EFIAPI\r
InitializeSpinLock (\r
  OUT     SPIN_LOCK                 *SpinLock\r
  )\r
{\r
  ASSERT (SpinLock != NULL);\r
\r
  _ReadWriteBarrier();\r
  *SpinLock = SPIN_LOCK_RELEASED;\r
  _ReadWriteBarrier();\r
\r
  return SpinLock;\r
}\r
\r
/**\r
  Waits until a spin lock can be placed in the acquired state.\r
\r
  This function checks the state of the spin lock specified by SpinLock. If\r
  SpinLock is in the released state, then this function places SpinLock in the\r
  acquired state and returns SpinLock. Otherwise, this function waits\r
  indefinitely for the spin lock to be released, and then places it in the\r
  acquired state and returns SpinLock. All state transitions of SpinLock must\r
  be performed using MP safe mechanisms.\r
\r
  If SpinLock is NULL, then ASSERT().\r
  If SpinLock was not initialized with InitializeSpinLock(), then ASSERT().\r
  If PcdSpinLockTimeout is not zero, and SpinLock is can not be acquired in\r
  PcdSpinLockTimeout microseconds, then ASSERT().\r
\r
  @param  SpinLock  A pointer to the spin lock to place in the acquired state.\r
\r
  @return SpinLock\r
\r
**/\r
SPIN_LOCK *\r
EFIAPI\r
AcquireSpinLock (\r
  IN OUT  SPIN_LOCK                 *SpinLock\r
  )\r
{\r
  UINT64                            Tick;\r
  UINT64                            Start, End;\r
  UINT64                            Timeout;\r
\r
  Tick = 0;\r
  Start = 0;\r
  End = 0;\r
  if (PcdGet32 (PcdSpinLockTimeout) > 0) {\r
    Tick = GetPerformanceCounter ();\r
    Timeout = DivU64x32 (\r
                MultU64x32 (\r
                  GetPerformanceCounterProperties (&Start, &End),\r
                  PcdGet32 (PcdSpinLockTimeout)\r
                  ),\r
                1000000\r
                );\r
    if (Start < End) {\r
      Tick += Timeout;\r
    } else {\r
      Tick -= Timeout;\r
    }\r
  }\r
\r
  while (!AcquireSpinLockOrFail (SpinLock)) {\r
    CpuPause ();\r
    ASSERT ((Start < End) ^ (Tick <= GetPerformanceCounter ()));\r
  }\r
  return SpinLock;\r
}\r
\r
/**\r
  Attempts to place a spin lock in the acquired state.\r
\r
  This function checks the state of the spin lock specified by SpinLock. If\r
  SpinLock is in the released state, then this function places SpinLock in the\r
  acquired state and returns TRUE. Otherwise, FALSE is returned. All state\r
  transitions of SpinLock must be performed using MP safe mechanisms.\r
\r
  If SpinLock is NULL, then ASSERT().\r
  If SpinLock was not initialized with InitializeSpinLock(), then ASSERT().\r
\r
  @param  SpinLock  A pointer to the spin lock to place in the acquired state.\r
\r
  @retval TRUE  SpinLock was placed in the acquired state.\r
  @retval FALSE SpinLock could not be acquired.\r
\r
**/\r
BOOLEAN\r
EFIAPI\r
AcquireSpinLockOrFail (\r
  IN OUT  SPIN_LOCK                 *SpinLock\r
  )\r
{\r
  SPIN_LOCK   LockValue;\r
  VOID        *Result;\r
  \r
  ASSERT (SpinLock != NULL);\r
\r
  LockValue = *SpinLock;\r
  ASSERT (LockValue == SPIN_LOCK_ACQUIRED || LockValue == SPIN_LOCK_RELEASED);\r
\r
  _ReadWriteBarrier ();\r
  Result = InterlockedCompareExchangePointer (\r
             (VOID**)SpinLock,\r
             (VOID*)SPIN_LOCK_RELEASED,\r
             (VOID*)SPIN_LOCK_ACQUIRED\r
           );\r
\r
  _ReadWriteBarrier ();\r
  return (BOOLEAN) (Result == (VOID*) SPIN_LOCK_RELEASED);\r
}\r
\r
/**\r
  Releases a spin lock.\r
\r
  This function places the spin lock specified by SpinLock in the release state\r
  and returns SpinLock.\r
\r
  If SpinLock is NULL, then ASSERT().\r
  If SpinLock was not initialized with InitializeSpinLock(), then ASSERT().\r
\r
  @param  SpinLock  A pointer to the spin lock to release.\r
\r
  @return SpinLock\r
\r
**/\r
SPIN_LOCK *\r
EFIAPI\r
ReleaseSpinLock (\r
  IN OUT  SPIN_LOCK                 *SpinLock\r
  )\r
{\r
  SPIN_LOCK    LockValue;\r
\r
  ASSERT (SpinLock != NULL);\r
\r
  LockValue = *SpinLock;\r
  ASSERT (LockValue == SPIN_LOCK_ACQUIRED || LockValue == SPIN_LOCK_RELEASED);\r
\r
  _ReadWriteBarrier ();\r
  *SpinLock = SPIN_LOCK_RELEASED;\r
  _ReadWriteBarrier ();\r
\r
  return SpinLock;\r
}\r
\r
/**\r
  Performs an atomic increment of an 32-bit unsigned integer.\r
\r
  Performs an atomic increment of the 32-bit unsigned integer specified by\r
  Value and returns the incremented value. The increment operation must be\r
  performed using MP safe mechanisms. The state of the return value is not\r
  guaranteed to be MP safe.\r
\r
  If Value is NULL, then ASSERT().\r
\r
  @param  Value A pointer to the 32-bit value to increment.\r
\r
  @return The incremented value.\r
\r
**/\r
UINT32\r
EFIAPI\r
InterlockedIncrement (\r
  IN      UINT32                    *Value\r
  )\r
{\r
  ASSERT (Value != NULL);\r
  return InternalSyncIncrement (Value);\r
}\r
\r
/**\r
  Performs an atomic decrement of an 32-bit unsigned integer.\r
\r
  Performs an atomic decrement of the 32-bit unsigned integer specified by\r
  Value and returns the decremented value. The decrement operation must be\r
  performed using MP safe mechanisms. The state of the return value is not\r
  guaranteed to be MP safe.\r
\r
  If Value is NULL, then ASSERT().\r
\r
  @param  Value A pointer to the 32-bit value to decrement.\r
\r
  @return The decremented value.\r
\r
**/\r
UINT32\r
EFIAPI\r
InterlockedDecrement (\r
  IN      UINT32                    *Value\r
  )\r
{\r
  ASSERT (Value != NULL);\r
  return InternalSyncDecrement (Value);\r
}\r
\r
/**\r
  Performs an atomic compare exchange operation on a 32-bit unsigned integer.\r
\r
  Performs an atomic compare exchange operation on the 32-bit unsigned integer\r
  specified by Value.  If Value is equal to CompareValue, then Value is set to \r
  ExchangeValue and CompareValue is returned.  If Value is not equal to CompareValue,\r
  then Value is returned.  The compare exchange operation must be performed using \r
  MP safe mechanisms.\r
\r
  If Value is NULL, then ASSERT().\r
\r
  @param  Value         A pointer to the 32-bit value for the compare exchange\r
                        operation.\r
  @param  CompareValue  32-bit value used in compare operation.\r
  @param  ExchangeValue 32-bit value used in exchange operation.\r
\r
  @return The original *Value before exchange.\r
\r
**/\r
UINT32\r
EFIAPI\r
InterlockedCompareExchange32 (\r
  IN OUT  UINT32                    *Value,\r
  IN      UINT32                    CompareValue,\r
  IN      UINT32                    ExchangeValue\r
  )\r
{\r
  ASSERT (Value != NULL);\r
  return InternalSyncCompareExchange32 (Value, CompareValue, ExchangeValue);\r
}\r
\r
/**\r
  Performs an atomic compare exchange operation on a 64-bit unsigned integer.\r
\r
  Performs an atomic compare exchange operation on the 64-bit unsigned integer specified \r
  by Value.  If Value is equal to CompareValue, then Value is set to ExchangeValue and \r
  CompareValue is returned.  If Value is not equal to CompareValue, then Value is returned. \r
  The compare exchange operation must be performed using MP safe mechanisms.\r
\r
  If Value is NULL, then ASSERT().\r
\r
  @param  Value         A pointer to the 64-bit value for the compare exchange\r
                        operation.\r
  @param  CompareValue  64-bit value used in compare operation.\r
  @param  ExchangeValue 64-bit value used in exchange operation.\r
\r
  @return The original *Value before exchange.\r
\r
**/\r
UINT64\r
EFIAPI\r
InterlockedCompareExchange64 (\r
  IN OUT  UINT64                    *Value,\r
  IN      UINT64                    CompareValue,\r
  IN      UINT64                    ExchangeValue\r
  )\r
{\r
  ASSERT (Value != NULL);\r
  return InternalSyncCompareExchange64 (Value, CompareValue, ExchangeValue);\r
}\r
\r
/**\r
  Performs an atomic compare exchange operation on a pointer value.\r
\r
  Performs an atomic compare exchange operation on the pointer value specified\r
  by Value. If Value is equal to CompareValue, then Value is set to\r
  ExchangeValue and CompareValue is returned. If Value is not equal to\r
  CompareValue, then Value is returned. The compare exchange operation must be\r
  performed using MP safe mechanisms.\r
\r
  If Value is NULL, then ASSERT().\r
\r
  @param  Value         A pointer to the pointer value for the compare exchange\r
                        operation.\r
  @param  CompareValue  Pointer value used in compare operation.\r
  @param  ExchangeValue Pointer value used in exchange operation.\r
\r
**/\r
VOID *\r
EFIAPI\r
InterlockedCompareExchangePointer (\r
  IN OUT  VOID                      **Value,\r
  IN      VOID                      *CompareValue,\r
  IN      VOID                      *ExchangeValue\r
  )\r
{\r
  UINT8  SizeOfValue;\r
\r
  SizeOfValue = sizeof (*Value);\r
\r
  switch (SizeOfValue) {\r
    case sizeof (UINT32):\r
      return (VOID*)(UINTN)InterlockedCompareExchange32 (\r
                             (UINT32*)Value,\r
                             (UINT32)(UINTN)CompareValue,\r
                             (UINT32)(UINTN)ExchangeValue\r
                             );\r
    case sizeof (UINT64):\r
      return (VOID*)(UINTN)InterlockedCompareExchange64 (\r
                             (UINT64*)Value,\r
                             (UINT64)(UINTN)CompareValue,\r
                             (UINT64)(UINTN)ExchangeValue\r
                             );\r
    default:\r
      ASSERT (FALSE);\r
      return NULL;\r
  }\r
}\r
Commit	Line	Data
878ddf1f	1	/** @file\r
	2	Implementation of synchronization functions.\r
	3	\r
ef7baf58	4	Copyright (c) 2006 - 2007, Intel Corporation<BR>\r
878ddf1f	5	All rights reserved. This program and the accompanying materials\r
	6	are licensed and made available under the terms and conditions of the BSD License\r
	7	which accompanies this distribution. The full text of the license may be found at\r
	8	http://opensource.org/licenses/bsd-license.php\r
	9	\r
	10	THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,\r
	11	WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.\r
	12	\r
ef7baf58	13	Module Name: SynchronizationMsc.c\r
878ddf1f	14	\r
	15	**/\r
	16	\r
58251024	17	#include "BaseLibInternals.h"\r
58251024	18	\r
eb9603a0	19	//\r
ef7baf58	20	// Microsoft Visual Studio 7.1 Function Prototypes for read write barrier Intrinsics\r
eb9603a0	21	//\r
ef7baf58	22	void _ReadWriteBarrier (void);\r
	23	#pragma intrinsic(_ReadWriteBarrier)\r
	24	\r
	25	\r
46dd23b8	26	#define SPIN_LOCK_RELEASED ((UINTN) 1)\r
46dd23b8	27	#define SPIN_LOCK_ACQUIRED ((UINTN) 2)\r
878ddf1f	28	\r
878ddf1f	29	/**\r
	30	Retrieves the architecture specific spin lock alignment requirements for\r
	31	optimal spin lock performance.\r
	32	\r
	33	This function retrieves the spin lock alignment requirements for optimal\r
	34	performance on a given CPU architecture. The spin lock alignment must be a\r
	35	power of two and is returned by this function. If there are no alignment\r
	36	requirements, then 1 must be returned. The spin lock synchronization\r
	37	functions must function correctly if the spin lock size and alignment values\r
	38	returned by this function are not used at all. These values are hints to the\r
	39	consumers of the spin lock synchronization functions to obtain optimal spin\r
	40	lock performance.\r
	41	\r
	42	@return The architecture specific spin lock alignment.\r
	43	\r
	44	**/\r
	45	UINTN\r
	46	EFIAPI\r
	47	GetSpinLockProperties (\r
	48	VOID\r
	49	)\r
	50	{\r
	51	// @bug May use a PCD entry to determine this alignment.\r
	52	return 32;\r
	53	}\r
	54	\r
	55	/**\r
	56	Initializes a spin lock to the released state and returns the spin lock.\r
	57	\r
	58	This function initializes the spin lock specified by SpinLock to the released\r
	59	state, and returns SpinLock. Optimal performance can be achieved by calling\r
	60	GetSpinLockProperties() to determine the size and alignment requirements for\r
	61	SpinLock.\r
	62	\r
	63	If SpinLock is NULL, then ASSERT().\r
	64	\r
	65	@param SpinLock A pointer to the spin lock to initialize to the released\r
	66	state.\r
	67	\r
	68	@return SpinLock\r
	69	\r
	70	**/\r
	71	SPIN_LOCK *\r
	72	EFIAPI\r
	73	InitializeSpinLock (\r
	74	OUT SPIN_LOCK *SpinLock\r
	75	)\r
	76	{\r
	77	ASSERT (SpinLock != NULL);\r
ef7baf58	78	\r
ef7baf58	79	_ReadWriteBarrier();\r
27787243	80	*SpinLock = SPIN_LOCK_RELEASED;\r
ef7baf58	81	_ReadWriteBarrier();\r
ef7baf58	82	\r
878ddf1f	83	return SpinLock;\r
	84	}\r
	85	\r
	86	/**\r
	87	Waits until a spin lock can be placed in the acquired state.\r
	88	\r
	89	This function checks the state of the spin lock specified by SpinLock. If\r
	90	SpinLock is in the released state, then this function places SpinLock in the\r
	91	acquired state and returns SpinLock. Otherwise, this function waits\r
	92	indefinitely for the spin lock to be released, and then places it in the\r
	93	acquired state and returns SpinLock. All state transitions of SpinLock must\r
	94	be performed using MP safe mechanisms.\r
	95	\r
	96	If SpinLock is NULL, then ASSERT().\r
	97	If SpinLock was not initialized with InitializeSpinLock(), then ASSERT().\r
	98	If PcdSpinLockTimeout is not zero, and SpinLock is can not be acquired in\r
	99	PcdSpinLockTimeout microseconds, then ASSERT().\r
	100	\r
	101	@param SpinLock A pointer to the spin lock to place in the acquired state.\r
	102	\r
	103	@return SpinLock\r
	104	\r
	105	**/\r
	106	SPIN_LOCK *\r
	107	EFIAPI\r
	108	AcquireSpinLock (\r
	109	IN OUT SPIN_LOCK *SpinLock\r
	110	)\r
	111	{\r
	112	UINT64 Tick;\r
	113	UINT64 Start, End;\r
	114	UINT64 Timeout;\r
	115	\r
	116	Tick = 0;\r
	117	Start = 0;\r
	118	End = 0;\r
dc530c7b	119	if (PcdGet32 (PcdSpinLockTimeout) > 0) {\r
878ddf1f	120	Tick = GetPerformanceCounter ();\r
	121	Timeout = DivU64x32 (\r
	122	MultU64x32 (\r
	123	GetPerformanceCounterProperties (&Start, &End),\r
dc530c7b	124	PcdGet32 (PcdSpinLockTimeout)\r
878ddf1f	125	),\r
	126	1000000\r
	127	);\r
	128	if (Start < End) {\r
	129	Tick += Timeout;\r
	130	} else {\r
	131	Tick -= Timeout;\r
	132	}\r
	133	}\r
	134	\r
	135	while (!AcquireSpinLockOrFail (SpinLock)) {\r
	136	CpuPause ();\r
	137	ASSERT ((Start < End) ^ (Tick <= GetPerformanceCounter ()));\r
	138	}\r
	139	return SpinLock;\r
	140	}\r
	141	\r
	142	/**\r
	143	Attempts to place a spin lock in the acquired state.\r
	144	\r
	145	This function checks the state of the spin lock specified by SpinLock. If\r
	146	SpinLock is in the released state, then this function places SpinLock in the\r
	147	acquired state and returns TRUE. Otherwise, FALSE is returned. All state\r
	148	transitions of SpinLock must be performed using MP safe mechanisms.\r
	149	\r
	150	If SpinLock is NULL, then ASSERT().\r
	151	If SpinLock was not initialized with InitializeSpinLock(), then ASSERT().\r
	152	\r
	153	@param SpinLock A pointer to the spin lock to place in the acquired state.\r
	154	\r
	155	@retval TRUE SpinLock was placed in the acquired state.\r
	156	@retval FALSE SpinLock could not be acquired.\r
	157	\r
	158	**/\r
	159	BOOLEAN\r
	160	EFIAPI\r
	161	AcquireSpinLockOrFail (\r
	162	IN OUT SPIN_LOCK *SpinLock\r
	163	)\r
	164	{\r
a4e9aab9	165	SPIN_LOCK LockValue;\r
a4e9aab9	166	VOID *Result;\r
ef7baf58	167	\r
878ddf1f	168	ASSERT (SpinLock != NULL);\r
a4e9aab9	169	\r
	170	LockValue = *SpinLock;\r
	171	ASSERT (LockValue == SPIN_LOCK_ACQUIRED \|\| LockValue == SPIN_LOCK_RELEASED);\r
c9708ddd	172	\r
ef7baf58	173	_ReadWriteBarrier ();\r
ef7baf58	174	Result = InterlockedCompareExchangePointer (\r
878ddf1f	175	(VOID**)SpinLock,\r
	176	(VOID*)SPIN_LOCK_RELEASED,\r
	177	(VOID*)SPIN_LOCK_ACQUIRED\r
878ddf1f	178	);\r
ef7baf58	179	\r
	180	_ReadWriteBarrier ();\r
	181	return (BOOLEAN) (Result == (VOID*) SPIN_LOCK_RELEASED);\r
878ddf1f	182	}\r
	183	\r
	184	/**\r
	185	Releases a spin lock.\r
	186	\r
	187	This function places the spin lock specified by SpinLock in the release state\r
	188	and returns SpinLock.\r
	189	\r
	190	If SpinLock is NULL, then ASSERT().\r
	191	If SpinLock was not initialized with InitializeSpinLock(), then ASSERT().\r
	192	\r
	193	@param SpinLock A pointer to the spin lock to release.\r
	194	\r
	195	@return SpinLock\r
	196	\r
	197	**/\r
	198	SPIN_LOCK *\r
	199	EFIAPI\r
	200	ReleaseSpinLock (\r
	201	IN OUT SPIN_LOCK *SpinLock\r
	202	)\r
	203	{\r
a4e9aab9	204	SPIN_LOCK LockValue;\r
a4e9aab9	205	\r
878ddf1f	206	ASSERT (SpinLock != NULL);\r
a4e9aab9	207	\r
	208	LockValue = *SpinLock;\r
	209	ASSERT (LockValue == SPIN_LOCK_ACQUIRED \|\| LockValue == SPIN_LOCK_RELEASED);\r
c9708ddd	210	\r
ef7baf58	211	_ReadWriteBarrier ();\r
27787243	212	*SpinLock = SPIN_LOCK_RELEASED;\r
ef7baf58	213	_ReadWriteBarrier ();\r
ef7baf58	214	\r
878ddf1f	215	return SpinLock;\r
	216	}\r
	217	\r
	218	/**\r
	219	Performs an atomic increment of an 32-bit unsigned integer.\r
	220	\r
	221	Performs an atomic increment of the 32-bit unsigned integer specified by\r
	222	Value and returns the incremented value. The increment operation must be\r
	223	performed using MP safe mechanisms. The state of the return value is not\r
	224	guaranteed to be MP safe.\r
	225	\r
	226	If Value is NULL, then ASSERT().\r
	227	\r
	228	@param Value A pointer to the 32-bit value to increment.\r
	229	\r
	230	@return The incremented value.\r
	231	\r
	232	**/\r
	233	UINT32\r
	234	EFIAPI\r
	235	InterlockedIncrement (\r
	236	IN UINT32 *Value\r
	237	)\r
	238	{\r
	239	ASSERT (Value != NULL);\r
	240	return InternalSyncIncrement (Value);\r
	241	}\r
	242	\r
	243	/**\r
	244	Performs an atomic decrement of an 32-bit unsigned integer.\r
	245	\r
	246	Performs an atomic decrement of the 32-bit unsigned integer specified by\r
	247	Value and returns the decremented value. The decrement operation must be\r
	248	performed using MP safe mechanisms. The state of the return value is not\r
	249	guaranteed to be MP safe.\r
	250	\r
	251	If Value is NULL, then ASSERT().\r
	252	\r
	253	@param Value A pointer to the 32-bit value to decrement.\r
	254	\r
	255	@return The decremented value.\r
	256	\r
	257	**/\r
	258	UINT32\r
	259	EFIAPI\r
	260	InterlockedDecrement (\r
	261	IN UINT32 *Value\r
	262	)\r
	263	{\r
	264	ASSERT (Value != NULL);\r
	265	return InternalSyncDecrement (Value);\r
	266	}\r
	267	\r
	268	/**\r
	269	Performs an atomic compare exchange operation on a 32-bit unsigned integer.\r
	270	\r
1ea5ca46	271	Performs an atomic compare exchange operation on the 32-bit unsigned integer\r
	272	specified by Value. If Value is equal to CompareValue, then Value is set to \r
	273	ExchangeValue and CompareValue is returned. If Value is not equal to CompareValue,\r
	274	then Value is returned. The compare exchange operation must be performed using \r
	275	MP safe mechanisms.\r
	276	\r
	277	If Value is NULL, then ASSERT().\r
	278	\r
878ddf1f	279	@param Value A pointer to the 32-bit value for the compare exchange\r
	280	operation.\r
	281	@param CompareValue 32-bit value used in compare operation.\r
	282	@param ExchangeValue 32-bit value used in exchange operation.\r
	283	\r
	284	@return The original *Value before exchange.\r
	285	\r
	286	**/\r
	287	UINT32\r
	288	EFIAPI\r
	289	InterlockedCompareExchange32 (\r
0ffa1286	290	IN OUT UINT32 *Value,\r
878ddf1f	291	IN UINT32 CompareValue,\r
	292	IN UINT32 ExchangeValue\r
	293	)\r
	294	{\r
	295	ASSERT (Value != NULL);\r
	296	return InternalSyncCompareExchange32 (Value, CompareValue, ExchangeValue);\r
	297	}\r
	298	\r
	299	/**\r
	300	Performs an atomic compare exchange operation on a 64-bit unsigned integer.\r
	301	\r
1ea5ca46	302	Performs an atomic compare exchange operation on the 64-bit unsigned integer specified \r
	303	by Value. If Value is equal to CompareValue, then Value is set to ExchangeValue and \r
	304	CompareValue is returned. If Value is not equal to CompareValue, then Value is returned. \r
	305	The compare exchange operation must be performed using MP safe mechanisms.\r
	306	\r
	307	If Value is NULL, then ASSERT().\r
	308	\r
878ddf1f	309	@param Value A pointer to the 64-bit value for the compare exchange\r
	310	operation.\r
	311	@param CompareValue 64-bit value used in compare operation.\r
	312	@param ExchangeValue 64-bit value used in exchange operation.\r
	313	\r
	314	@return The original *Value before exchange.\r
	315	\r
	316	**/\r
	317	UINT64\r
	318	EFIAPI\r
	319	InterlockedCompareExchange64 (\r
0ffa1286	320	IN OUT UINT64 *Value,\r
878ddf1f	321	IN UINT64 CompareValue,\r
	322	IN UINT64 ExchangeValue\r
	323	)\r
	324	{\r
	325	ASSERT (Value != NULL);\r
	326	return InternalSyncCompareExchange64 (Value, CompareValue, ExchangeValue);\r
	327	}\r
	328	\r
	329	/**\r
	330	Performs an atomic compare exchange operation on a pointer value.\r
	331	\r
	332	Performs an atomic compare exchange operation on the pointer value specified\r
	333	by Value. If Value is equal to CompareValue, then Value is set to\r
	334	ExchangeValue and CompareValue is returned. If Value is not equal to\r
	335	CompareValue, then Value is returned. The compare exchange operation must be\r
	336	performed using MP safe mechanisms.\r
	337	\r
	338	If Value is NULL, then ASSERT().\r
	339	\r
	340	@param Value A pointer to the pointer value for the compare exchange\r
	341	operation.\r
	342	@param CompareValue Pointer value used in compare operation.\r
	343	@param ExchangeValue Pointer value used in exchange operation.\r
	344	\r
	345	**/\r
	346	VOID *\r
	347	EFIAPI\r
	348	InterlockedCompareExchangePointer (\r
0ffa1286	349	IN OUT VOID **Value,\r
878ddf1f	350	IN VOID *CompareValue,\r
	351	IN VOID *ExchangeValue\r
	352	)\r
	353	{\r
58251024	354	UINT8 SizeOfValue;\r
	355	\r
	356	SizeOfValue = sizeof (*Value);\r
	357	\r
	358	switch (SizeOfValue) {\r
878ddf1f	359	case sizeof (UINT32):\r
	360	return (VOID*)(UINTN)InterlockedCompareExchange32 (\r
	361	(UINT32*)Value,\r
	362	(UINT32)(UINTN)CompareValue,\r
	363	(UINT32)(UINTN)ExchangeValue\r
	364	);\r
	365	case sizeof (UINT64):\r
	366	return (VOID*)(UINTN)InterlockedCompareExchange64 (\r
	367	(UINT64*)Value,\r
	368	(UINT64)(UINTN)CompareValue,\r
	369	(UINT64)(UINTN)ExchangeValue\r
	370	);\r
	371	default:\r
	372	ASSERT (FALSE);\r
	373	return NULL;\r
	374	}\r
	375	}\r